West Pacific/2015/09W/Archive/10
Update TROPICAL STORM CHAN-HOM TROPICAL CYCLONE UPDATE WIKI-HURRICANES FORECASTING CENTER 10:00 PM JST THU JUL 02 2015 ...CHAN-HOM DEEPENS.... The intensity is being increased to 55 knts based on current satellite estimates and the possible formation of a microwave eye. SUMMARY OF 6:00 PM JST...09:00 UTC...INFORMATION ------------------------------------------------------------------- LOCATION...11.2N 149.9E CENTER POSITION CONFIDENCE: LOW ABOUT 600 MI...965 KM WNW OF PALIKIR, MICRONESIA ABOUT 450 MI...725 KM ESE OF GUAM MAXIMUM SUSTAINED WINDS...55 KT...60 MPH...105 KM/H MINIMUM BAROMETRIC PRESSURE...993 MB...29.32 INCHES PRESENT MOVEMENT...WNW AT 16 KT...18 MPH...29 KM/H Public advisory TROPICAL STORM CHAN-HOM PUBLIC ADVISORY NUMBER 10 WIKI-HURRICANES FORECASTING CENTER 6:00 PM JST THU JUL 02 2015 ...CHAN-HOM WEAKENS... SUMMARY OF 6:00 PM JST...09:00 UTC...INFORMATION ------------------------------------------------------------------- LOCATION...11.3N 150.5E CENTER POSITION CONFIDENCE: LOW ABOUT 580 MI...930 KM WNW OF PALIKIR, MICRONESIA ABOUT 430 MI...725 KM ESE OF GUAM MAXIMUM SUSTAINED WINDS...45 KT...50 MPH...95 KM/H MINIMUM BAROMETRIC PRESSURE...998 MB...29.30 INCHES PRESENT MOVEMENT...WNW AT 16 KT...18 MPH...29 KM/H DISCUSSION AND 48-HOUR OUTLOOK --------------------------------------------- At 6:00 am JST, the center of Tropical Storm Chan-Hom was situated near 11.3N, 150.5E, about 570 miles (915 km) west-northwest of Palikir, Micronesia, or about 450 miles (725 km) east-southeast of Guam. Maximum sustained winds were 4 knots (50 mph, 80 km/h), with higher gusts. The minimum barometric pressure was 996 millibars (hPa; 29.41 inHg), and the cyclone was tracking west at 16 knots (18 mph, 29 km/h). Steady strengthening is expected over the next 48 hours, succeeded by more rapid intensification thereafter. On its current forecast track, Chan-hom poses a substantial threat to the central and southern Mariana Islands, and residents there should monitor the progress of the cyclone closely. NEXT ADVISORY ------------------- Next complete advisory at 6:00 pm JST. $$ Forecaster YE Discussion TROPICAL STORM CHAN-HOM DISCUSSION NUMBER 10 WIKI-HURRICANES FORECASTING CENTER 6:00 PM JST THU JUL 02 2015 Tropical Storm Chan-hom continues to be poorly organized this evening. The center of Babble is once again naked and a bit exposed. Furthermore, the MLC and LLC remain separate with a SSMIS pass from this morning showing a well-defined MLC under the CDO. Sinc erthen, the CDO itself has rapidly became less organized and cloud tops have warmed. A blend of subjective and objective estimates support lowering the winds to 45 knts, which is long overdue, and even if based it on satellite presentation, 45 would seems as generous as granting teacher granting an 89.0% student an A. Based on the cyclone's satellite presentation, Chan-hom continues to feel the effects of moderate easterly wind shear due to a displaced upper-level area of high pressure. In fact, maps made by UW-CIMSS indicate that such shear is persistently in the range of 20 to 30 knots. Another potential inhibitor is the quick forward motion of the cyclone, which may be introducing speed shear in an already unfavorable environment. However, over the coming days, this is all going to change. The upper-level setup is expected to become exceptionally conducive as an anticyclone builds aloft. An upper-level low moving north to the cyclone's north should also provide a poleward outflow channel, beneficial to the storm's intensification rate. Sea surface temperatures and ocean heat content values are also expected to remain conducive for further organization and if anything, both increase over the next several days. Both global and hurricane models continue to indicate that Chan-hom will become a large and powerful typhoon over the coming days, with all guidance suggesting a pressure under 930mb by day 5, and the 0z GFS bringing it 897 mbar by day 5, 867 mbar at peak, which would make it the strongest system of all time, and 873mbar when it slams into Okinawa, which in the event it verifies, could be catastrophic their. While the new intensity forecast is lower in the short-term to account for arrested development typical of tropical cyclones and as such, users who are anticipating such a potent tropical cyclone are advised to not panic, it shows a real rapid intensification period now, which is becoming more and more likely. However, this is not likely to take place until the LLC and MLC align, which could take a while. As has been the case most of the day, Chan-hom is continuing on a swift westward motion. The forecast philosophy for the storm is unchanged. The cyclone is being steered by a mid-level ridge to its north. Global modelling suggests that this ridge may even intensify over the coming day or so, forcing Chan-hom on a west-southwest track. However, by 48 hours, a series of upper-level troughs digging into Japan and surrounding regions is expected to erode the western side of the ridge and force the to be deepening typhoon on a northwesterly course. The updated forecast track is very close to the previous one. On the current path, Chan-hom is expected to pose a substantial threat to the central and southern Mariana Islands. INIT 02/0900Z 11.3N 150.5E 45 KT 50 MPH 12H 02/1800Z 11.3N 148.9E 45 KT 50 MPH 24H 03/0600Z 11.3N 147.E 50 KT 60 MPH 36H 03/1800Z 11.4N 146.8E 55 KT 65 MPH 48H 04/0600Z 12.4N 1465.8E 70 KT 80 MPH 72H 05/0600Z 15.6N 143.4E 100 KT 115 MPH 96H 06/0600Z 18.9N 141.2E 125 KT 145 MPH 120H 07/0600Z 21.5N 137.8E 140 KT 160 MPH $$ Forecaster YE